| C2C | CA | Cache | Cache Poisoning | CAPI | CAPTCHA | Carnivore | CC | CCITT | ccTLD | CDF | CDMA | CDNS | CDS | Censorware | Centr | CEPT | CERN | CERT/CC | CFML | CGI | Chain Letter | Channel | CHAP | Charta | Chat | Cheapernet | Chiffrierung | CIDR | CIFS | CIS | Cisco Systems, Inc. | CIX | CLF | Clickjacking | Click Through | Client | Client-/Server-Architektur | Cloaking | CMIP | CML | CMS | Co-Domain | ColdFusion | Collaborative Filtering | COM | Community | Company_ID | Conference | Content Provider | Content Syndication | Cookie | CORBA | CORE | Courtesy Top-Level Domain | CPC | Cracker | CRC | Crippleware | CRISP | CRL | Cross Connect Cable | Cross Posting | CSMA/CA | CSMA/CD | CSNET | CSP | CSS | CTR | CUAP | Curl Corp. | CVS | Cybergeografie | Cyberspace | Cybersquatter